1. Field of the Invention
The present invention relates to paper machine clothing, especially a press felt for a paper-, cardboard- or tissue machine, as well as to a method for producing the paper machine clothing.
2. Description of the Related Art
Paper machine clothing, especially press felts for paper-, cardboard- or tissue machines normally include a basic structure which provides the dimensional stability of the felt, and which is furnished with one or more fibrous nonwoven layers.
In the past the objective in the development of new press felts was to replace the felt belts through a modular composition of individual components and to thereby replace woven structures, since woven structures can only be produced with low productivity.
WO89/03300, for example, shows press felts composed of modules. Here, modules are suggested which are composed of a laid structure of longitudinal threads which is bonded with one fibrous nonwoven layer, as well as modules which consist of a laid structure of cross threads which is bonded with one fibrous nonwoven layer.
In order to simplify the production of modular press felts of this type it is further suggested in EP 1837440A1 to produce the tensile load bearing longitudinal reinforcement module from a laid structure of longitudinal threads which is bonded with a fibrous nonwoven layer in one winding process. The transverse-reinforcement module which is used to increase the transverse stability is constructed from several transverse-reinforcement module segments which extend only along part of the length of the press felt and which are produced in a first manufacturing step, also through a winding process like the longitudinal reinforcement module. In a subsequent manufacturing step, the transverse-reinforcement module segments are trimmed to the width of the press felt that is to be produced, oriented with their threads transversely to the laid structure of longitudinal threads, and arranged after one another in a longitudinal direction of the felt. A disadvantage of these transverse reinforcement structures is that they are produced from a laid structure of longitudinal threads which is ready-made to be used as a transverse reinforcement module and must be trimmed and which consist of a plurality of individual segments arranged after one another in the longitudinal direction of the press felt.
The known modular press felt concepts consist of laid structures of longitudinal threads and of laid structures of cross threads, whereby the two laid structures are bonded with each other through only one fibrous nonwoven layer. A disadvantage of these structures is that such laid structures often only provide a very limited void volume in the press felt. Also, since the laid structures of longitudinal and cross threads can move against each other, they move aside for each other when running through the press nip, which can lead to a further reduction of the void volume and consequently to a reduction in the water absorption capacity.
What is needed in the art is a paper machine clothing, especially a press felt, which maintains a substantially high void volume and which moreover is more cost effective than the press felts known from the current state of the art.